大합 !íH‘H~ 뽑 짝，t tr 픔、 짜 24 卷 第 1 號 pp. 98 - 103, 1988 Journal of Korean Radiological Society, 24(1) 98-103, 1988

The Inferior Accessory Hepatic Fissure:

〈國文헨‘錄 〉

An Anatomic Study U sing Cadaver and CT

Jae Hoon Lim, M.D., Young Tae Ko , M.D. and Kyung Nam Ryu . M.D.

Department of Radiology, Kyung Hee University Hospital

下훌IJJJf製의 解휩j

慶熙大學校 醫科大學 放射線科學敎室

林在勳·高永泰·柳京南

下副빠짧은 府右葉 後分節을 二分하는 冠狀面 或은 副失狀面으로 內測題題이 B정入된 煩性9꾸짧이

다. 著者들은 下副府짧의 模樣과 頻度를 알고자 14 顆의 死體땀과 100 f7lJ.91 題部 CT 를 觀察하였다.

死體府 14 顧中 8 顆에서 깊이 2~3cm ， 길이 3~4cm의 下副府짧이 觀察되었다. 題部CT 100 例中

11 f7l.에서는 2cm 정도의 下副府앓이 觀察되었고 46 í9l벼 CT에서는 양은 ßß沒이 存tE하였는데 이 중

많은 f7!에서 下副府앓이 存在할 것으로 推뼈된다. 따라서 府의 약 半數에서는 下副府짧이 存在

한다는 것을 確認하였다.

To assess th e shape and frequency of the inferior accessory hepatic fissure, authors observed 14 cadaveric

live rs and 100 abdominal ( T scans. The inferior accessory hepatic fi ssure was present in eight of 14 cadave ri c

live rs and eleven of 100 abdominal (T scans. A shall ow notch was present in 46 of 100 (T scans and many

。f these notches may represent either shallow or deep fissures . The inferior accessory hepatic fissure is not

a ra re anatomic va riation as the fissure was encountered in 11l0re than half of the cadavers and ( T scans

I. Introduction

The inferior accessory hepatic fissure is a

fissure through the parenchyma of the posterior

segment of the right h e patic lobe in a coronal

이 논운은 1 987 년 12월 30 알에 접수하여 1988 년 l

월 22 일에 채택되었음.

Received December 30, 1987, accepted January 22, 1988

or sagittal, or between the coronal and sagittal planes. It is a peritone a l invagination into the liver parenchyma directed la terally and poster-

iorly from the medial inferior surface of the

right hepatic lobe . Its sectional anatomic and sonographic appearances were described 1) •

Herein, we describe the shape and frequency of the fissure , based on a study of anatomic cadaver dissections and a bdominal CT scans.

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- Jae Hoon Lim. et al: The Inferior Accessory Hepatic F issure: An Anatomic Study Usi ng Cadaver and CT-

11. Materials and Methods

The inferior and medial surfaces of the livers of 14 cadavers were reviewed concentrating particu1ar importance on the shape and depth of the inferior accessory hepatic fissure. Ab-domina1 CT scans in 100 consecutive patients without 1iver masses were reviewed retrospec-tively. CT examinations were performed with a Toshiba TCT-80A scanner using 10mm co1-1imation and 9 sec scan times. Consecutive CT scans through the upper abdomen were done during deep inspiration, with the patient supine, at interva1s of 10-15mm. Ora1 and intravenous contrast media were administered in majority of cases . Antispasmodics (Buscopan@, Scopo1-amine buty1bromide , Boehringer 1nge1heim, Korea Limited , Seou1) was administered in-travenous1y to inhibit bowe1 perista1sis.

111. Results

Among the 14 cadaveric 1ivers, the inferior accessory hepatic fissure was persent in eight livers (Tab1e 1). The fissures were deep in three cases, the depth being some 2.5cm and 1ength being some 4cm (Fig. 1-a). Five 1ivers showed shallow fissures , the depth being 1ess than 1.5cm and the 1ength being 1ess than 2cm (Fig. 1-b). The fissure started from the right side of the porta hepatis just latera1 to the gallb1adder neck. 1n or between the corona1 and parasagit-ta1 p1anes, the fissure is a true invagination of the viscera1 peritoneum running downwards to

Table 1. Frequency of IAHF in 14 Cadavers.

Fissure Number

Deep fissure 3

Shallow fissure 5

Notch 4

No fissure 2

/ ~

a

b

c

Fig. 1 Anteroinferior surface of cadaveric livers

a. A cleepfissure (open arrow) separates the “ m-ferior accessory hepatic lobe (IAHL)" from the rest of the liver. The fissure extencls downwarcls and comes in direct contact with the anterior surface of the right kidney (retracted downwards). Note the relation between the fissure and the gallbladder (GB). C= caudate process (partly broken) of the caudate lobe b. A shallow fissure (arrow). GB = Gallbladder c. A notch (arrow) at the site of the inferior ac-cessory hepatic fissure ‘ GB = Gallbladder

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-大韓放射線醫웰會註 第 24 卷 第 1 號 1988-

the inferior surface of the liver. The fissure divided the inferior part of the posterior seg-ment into the anterolateral and posteromedial parts. Among the six livers without fissure , four livers showed a notch at the medial surface of the liver just lateral to the gallbladder neck, ex-actly the same site at the fissure (Fig. 1-c). The

a

c

remaining two livers have no trace of the fissure or notch at all.

In the series of 100 CT scan , accessory fissures were observed in eleven cases (Table 2). Thefissure measured some 2cm (Fig. 2-a). The fissure directed posterolaterally from the gallbladder neck. Shallow notches were observ-

Fig. 2 CT scans through the lower part of the liver in three c1 ifferent patients. a. A fissure is clearly c1 emonstratecl by fat within

’ the fissure (arrow) b. A notch at the site of the inferior accessory hepatic fissure (arrow). c. CT scan showing no eviclence of the fissure

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Table 2. Frequency of IAHF in 100 CT’s

Jae Hoon Lim. et al: The Inferi or Accessory Hepatic Fissure: An Anatomic Study Using Cadaver and CT-

Fissure Number

Fissure Notch No fissure

n a%

섭

ed in 46 cases (Fig. 2-b). The site of the not-ches was exactly the same area as the well developed fissure. 1n the remaining 43 cases, there was no trace of a fissure or notch (Fig. 2-c).

1V. Discussion

Topographically there are three major fissures in the liver 2-4). The interlobar fissure , or fissure for the gallbladder, lies along the Cantlie line, an imaginary line connecting the inferior vena cava and the gallbladder. It divides the liver into the right and the left lobes. The fissure for the ligamentum teres divides the left lobe into the lateral and medial segments. The fissure for the ligamentum venosum separates the caudate lobe posteriorly from the left lobe anteriorly. 1n addition to these three fissures , there is a shallow fissure in the inferior part of the right hepatic lobe. This fissure has not been discussed until recently. Lim et al') described the fissure in detail using transverse cadaveric sections and ultrasonic appearances and named the inferior accessory hepatic fissure.

On cadaveric livers, the depth of the fissure varied from a notch to a fissure some 3cm deep (Fig. l-a, b, c). Two of eight fissures were pret-ty deep and the liver parenchyma posteromedial to the fissure is clearly separated from the rest of the right hepatic lobe by the deep fissure (Fig. l-a). The separated hepatic parenchyma may be called “ inferior accessory hepatic lobe" since the accessoη hepatic lobe is defined as the hepatic tissue that was clearly super-numerary and attached to the remaining liver by a pedicle of liver tissue or mesentery6).

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b

Fig. 3 Inferior accessory hepatic fissure in patients with ascites. a. A transverse ultrasound scan in a patient with cirrhosis of the liver. The inferior accessory hepatic fissure is filled by ascitic fluid (arrow). RK = Right kidney. F = Ascitic fluid. b. A CT scan in another patient with cirrhosis of the liver. Arrow points in inferior accessory hepatic fi ssure fi lled by ascitic fluid. N = Lymphnode in the portocaval space

-大韓放射線醫탱會註 , 第 24 卷 第 1 號 1988-

The frequency of the inferior accessory hepatic fissure has not been known. Lim et al') reported 15 (0.8%) fissures out of 2000 ab-dominal sonogram. However, this rate is not a true incidence as the fissure is too thin and meager to be seen on ultrasonogram, especial-ly if a sonographer is not interested in the

a

b

fissure. The fissure was observed in eight (57%) of 14 cadavers (Fig. 1-a, b). Three livers have a deep fissure and five have a shallow fissure. On CT scans, however, the fissure was present in only eleven (11%) of 100 scans. This discrepancy between cadaveric and CT obser-vations is not surprising. The peritoneal in-

c

d

Fig. 4 Hypertrophy of the “ inferior accessory hepatic lobe" a,b,c. A hepatic parenchyma bulges downwards and contacts the anteríor surface of the ríght kídney (RK). This “ mass" simulates a pedunculated hepatoma. PP = Papillary process of the caudate lobe. CP = Caudate process of the caudate lobe. V=Inferior vena cava. GB=Gallbladder d. A parasagittal sonogram confirms the continua-tion of the liver parenchyma extending downwards. An echogenic line (arrows) represents the inferior accessory hepatic fissure

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- Jae Hoon L im. et al: The Inferior Accessory Hepatic Fissure: An Anatomic Study Us ing Cadaver and CT-

vagination contains various amount of fat. The less is the amount of fat in or between the fissure , the less is the chance of visualization on CT. This also explains such a low rate of visualization of the fissure on ultrasound 1 . 5). Mesenteric fat or ascites may fill the gap of the fissure and facilitate visualization on ultrasonogram and CT (fig. 3-a, b). A large number of livers in which a notch was visualiz-ed on CT scans (Fig. 2-b) probably have the in-ferior accessory hepatìc fissure. If many of these notches are considered to represent deep or shallow inferior accessory hepatic fissure , the overall frequency of the fissure is roundabout 60%. This rate is consistent with the frequen-cy observed in cadavers.

The relationship between the presence of the inferior accessory hepatic fissure and the overall anatomy of the liver is not certain. Lim te al described the close relationship between the fissure and the posterior branch of the right portal vein l). This suggests some possible rela-tionship between embryologïcal development of the liver and the fissure.

The significance of the fissure is uncertain. Sonographic or CT visualization of the fissure is important for localization of a tumor before surgeryl). Sometimes a pathologic process arises within the accessory lobe. We observed a case of hypertrophy of the “ inferior accessory hepatic lobe" mimicking a pedunculated

hepatoma (Fig. 4-a, b, c , d). A Surgeon may make use the fissure as a landmark in surgery. Furthermore, if the fissure is deep, it could be used as a guide for hepatic subsegmentectomy in patients with hepatic dysfunction.

In summaη， our cadaveric and CT study established relatively high frequency of the in-ferior accessory hepatic fissure. The fissure , if visualized on ultrasound or CT, may be useful in surgery in patient with diminished hepatic reservoir function.

REFERENCES

1. Lim JH, Ko YT, Han MC, et a/: The inferior accessory hepatic

fissure: Sonographic appearance. AjR 149: 495-497; 1987

2. Auh YH, Rubenstein WA, Zirinsky K, et a/’ Accessory

fissures of the /iver: CT and sonographic appearance. AjR

143: 565-572; 1984.

3. Sexton CC, Zeman RK: Corre/ation of computed

tomographκ sonographκ and gross anatomy of the /iver.

AjR 141: 711-718; 1983

4. Kane RA: Sonographic anatomy of the /iver. Seminar U/tar-

sound. 2: 190-19끼 1981.

5. Fried AM, Kreel L, Cosgrove DO: The hepatic interlobar

fissure: Combined in vitro and in vivo study. AjR 143:

561-564; 1984.

6. Cullen TS: Accessory /obes of the /iver.‘ Arch Surg 11

718-764; 1925

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